http://cgi.ebay.co.uk/RECTANGULAR-O...14&_trkparms=72:1683|66:2|65:12|39:2|240:1318

ive seen these on ebay but wat do they do and is it worth it.

thanks

They are for competition use, some series construction rules actually require them. The breather pipes will be routed to to the catch tank and any oil blown out at high revs or if any surges out under cornering forces it will end up in the catch tank, not all over the track. I spose you could put one on a road car for show. I did look for apic but can't find one

You don't fit them on road cars 'for show', they're fitted to stop contamination of the air going into the throttle body/inlet manifold and to give a cleaner running engine. Oil vapour has no place in an induction system but it's plumbed into there for legal reasons. Having an in-line tank with enough hose and capacity to let the vapour cool and be collected does the job fine and is still legal. It cannot vent to atmosphere.